Currently in many CVD installations, the cylinders of reactive gas are located as close as possible to the process tool. This results in an unsafe work environment. Industry has experienced flow problems when locating the cylinders of tungsten hexafluoride more than 35 feet from the process tool possibly because of the tendency of WF.sub.6 to react with any moisture it encounters, thereby forming an oxide which deposits in tubes in which the WF.sub.6 is flowing. The flow rate required for the CVD process presently does not exceed 500 standard cubic centimeters per minute (sccm) of WF.sub.6 delivered at the point of use. U.S. Pat. Nos. 4,640,221; 4,699,805 and 4,910,042 disclose and claim various systems for chemical vapor deposition (CVD) of thin coatings on a substrate, the '805 patent showing a CVD process for tungsten hexafluoride (WF.sub.6). U.S. Pat. No. 4,892,615 discloses and claims a purging system for use with various semi-conductor manufacturing devices.